Ebbinghaus, Stefan G. Krause, Holger Lee, Doh-Kwon Janek, Juergen 2024-01-20T10:01:05Z 2024-01-20T10:01:05Z 2021-09-05 2014-05 1528-7483 https://pubs.kist.re.kr/handle/201004/126844 Single crystals of Ca12Al14O33 (C12A7, mayenite) substituted with 1 mol % Fe were grown by the floating zone technique in an atmosphere of 2% O-2/98% N-2. The iron substitution leads to an increase of the unit cell parameter by roughly 0.002 angstrom. Optical spectroscopy reveals an additional broad absorption band at 310 nm for the iron-substituted sample reflecting the yellow color of the crystals. XANES measurements at the Fe-K absorption edge prove the incorporation of Fe3+ on the aluminum sites. Measurements of the magnetic susceptibility resulted in a value of 5.8 mu(B) per iron ion as expected for high-spin Fe3+. C12A7 is known to be a very good oxygen ion conductor at high temperatures. In pure oxygen, the iron substitution leads to a slightly reduced conductivity between approximately 500 and 800 degrees C, while at higher temperatures, the conductivity is very similar to the pristine material. Under reducing conditions, the slope of log(sigma) vs log(p(O-2)) of the iron-substituted sample was found to be steeper than that for pure C12A7. English American Chemical Society OXIDE-ION CONDUCTIVITY OXIDATION-STATE COORDINATION GROWTH RU Single Crystals of C12A7 (Ca12Al14O33) Substituted with 1 mol % Iron Article 10.1021/cg401823k 1 Crystal Growth & Design, v.14, no.5, pp.2240 - 2245 Crystal Growth & Design 14 5 2240 2245 scie scopus 000335879500024 2-s2.0-84900341062 Chemistry, Multidisciplinary Crystallography Materials Science, Multidisciplinary Chemistry Crystallography Materials Science Article OXIDE-ION CONDUCTIVITY OXIDATION-STATE COORDINATION GROWTH RU Mayenite C12A7 Fe ionic conductivity single crystal growth anti-zeolite floating zone technique iron substitution X-ray absorption spectroscopy UV-Vis spectroscopy